Closure operator for sliding doors



Sept. 11, 1928.

H. W. SHONNARD CLOSURE OPERATOR FOR SLIDING DOORS 2 Sheets-Sheet 1 Filed May 6, 1927 Sept. 11, 1928. 1 684 l H. w. SHONNARD 15 CLOSURE OPERATOR FOR SLIDING DOORS Filed Ilay 1927 2 Sheets-Sheet 2 0 QM 2 z w 2 Patented Sept. 11, 1928. I I UNlTE-D STATES HAROLD women-D; -01" UPPER mom mln, smwise sv, ee iozwn To summon SUPPLIES COMPANY, A ,0]? "NEW FTEQSEY.

CLOSURE OPERATOR FoRsLmI G poons.

Application filed May 6, 19,21. fieriel No. 139,1390.

This invention relates to closure operijitinf; means tor sliding doors, such as elevator doors, and has particular reference to that type of closure operator involving the use of ,a set of manually operable links, kno vn in :the art as toggle levers, together with vide -a means for relatively disposing the.

principal parts .ot the door operating mecha'nisinso as to obtain a more, efiective apphcation of the power contained in the po ver unit and at thesa netiinereduce to a 111mlinum the effort which must be expended by Ithe user or operator of the doors in moving theintovvard open position against theiresistance of the poiver unit.

Other objects and advantages to be derived from the use of the improved mecha-v nisni embodying this invention reside in the specific construction and manner of combining' the parts and Wlll become more ap parentfrom the following description when "me with reference to the accompanying drawings wherein like reference characters indicate like parts in the several views.

In the drawings Figure 1 is a view in elevation illustrating the application of thevinvention .to a set of sliding doors of the telescoping (diiierential speed) type.

Fieiuze 2 is a view on a larger scale oit'soine of the parts shown in Figure 1, showing the preferred type of closer unit in section. Figure 3 is a sectional view thru Figure 2 at line 3 ,:cs 4; and 5 t "51 the increase in eiiiciency obtained theuse of the present invention,

diagram shown for a Figure 6 is another similar purpose. 1

In the embodiment of the invention illustrated a pair of sliding doors 1 and 2. are shown mounted on a track 3 along which they are adapted to slide thru the instrumentality of suitable hang-er devices 4 preferably ellowing diflerential movement of thejdoors.

are -force diagrams illus- A pair of toggle flevers 5v an d 6 are shown provided for the purpose of enabling the IXilTSQI ing to operate the doors to open them ivitha minimum of efidrt. "As shown by Way o i u a ng h prefer ed em diment, the lever 6 is pivoted jet 7 to a bracket 8 near the outer edge of the :doorQ and pivoted at its other end to the lever '5 by means of the pivot pin 9, lever 5 in mm being pivotal-1y mounted to a' plate 10 attached to the inner edge of ldoor 1 The lever '5 is shown connected'at its other end by means f :P VQ Pi l o 3 .1 7 h ,l tt bel fi'g p v ta l'y uhnmt af a suitable pivot bearing 14 mounted on the framework The toggle lever 12 isshoi'vn provided with a dependingear 16 having "provision at fits ilovver end for the reception of a crank pivot 17, serving as a connecting .mez xrns between the lever 12 and the rod 18 constituting, in the i'ireferred embodiment, the actlljating member for the transmission of power from the power unit designated generally by, the eign n character 19.

In the preferred form as shown thepo-Wer, or closer, unit 19 coinprlses a substantially cylinclrical housing 20 provided ivith a I L dGJ 21 having su table pro-visions thereon for the support-0t the closer unit on the supporting lug 22 mounted on the framework 15. The rod 18 extends downwardly thru' .the housing 2.0 and .atits lower end is attached by suitable means, as pin 23, to a plunger Q4 the latter serving as a seat for the multiple coil spring 25 retained in the closer unit by suitablemeans which serve also .as a tension regulating device. In the construction \as shoivnthis means consists of a threaded cap 26 fitting into vthe upper .end of the housing 20 and serving to retain the desired tension on spring 25.

To provide means, [tor :loushioning the inoveinent of the doors the housing 20 is preferably filled with suitable cushioning fluid, such {as oil, and a bypass 30 is provided in the lower portion of the housing QO tO perniit passage of the fluid thru the housing froinone otthe plunger 24- to the other as the latter moves in a downward direction. Means for regulating the amount of the retard ation vexercised: ponthe plung er is provided preferably in the form of an adjusting screw 31 serving. to vary the ainountlot opening the bypass 30L The surface of the cylinder 20 comprises preferably a fluted construction consisting of alternate raised and depressed portions, the

raised surfaces '38 being adapted to act as guides for the plunger 24 and the depressed portions 39 permitting free passage of the cushioning fluid around the plunger 2 as the plunger moves along the portion of the cylinder having this construction. shown in Figure '2 this construction of the inner wall of the cylinder extends downwardly to the shoulder indicated at 39, this shoulder being formed at the lower end of that portion of the cylinder having the enlarged diameter, as shown at 37.

Suitable means, such as the washer 35 of some soft material, such as leather, is preferably interposed below the cap 26 and surroi'u'iding the plunger rod 18 to prevent leakage of the cushioning fluid around the rod 18 asit is drawn out of the cylinder 20. As shown the washer 35 is adapted to be held firmly in position by the interposition of another washer 36 of a stiffer material, such as a suitable metal. This washer 36 therefore serves as a stop or limiting means for upward motion of the spring 25.

lVith this construction the method of operation of the doors is as follows:

A person wishing to open the doors grasps e handle 34. on the toggle lever 5 and pulls n the downward direction, thereby breaking the toggle alignment and causing a movement of the doors 1 and 2 toward open position. As toggle lever 12 swings upwardly in response to this operation, the plunger rod and plunger are drawn upwardly and as a consequence the spring is c(, mpressed against the washer 36 which in turn bears against the cap 26. Now when the person who has thus caused an opening movement of the doors releases the restraint exercisml by him upon the toggle lovers, the plunger and plunger rod descend toward the lower end of the-housing in response to the urge of the spring 25. Downward move ment of the plunger causes a corresponding swing of the toggle levers 12, 5 and 6 and a consequent movement of the doors 1 and 2 back toward closed position.

As the plunger reaches a point in the housing 20 adjacent the shoulder 39 (which is the point where the cylinder diameter changes and the fluted construction ends) the passage of the oil from the lower portion ofthe housing becomes considerably impeded ancl'can be effected only by escape tion.

thru the restricted portionof the bypass 30. The effect of the restricted escape is to reduce the speed of the plunger, thereby causinglthe doors to come to astop gradually as tie Although the principles of opera'tioninvolved in the construction so far described are old, the-specific construction shown and the manner of mounting the parts, particularly the closer unit and the pivot bearing for the toggle levers, with respect to their relative disposition, are believed to be disclosed herein for the first time. Heretofore it has been customary to mount closing units of the general type of this disclosure plunger approaches its lowe'stposiby providing a supporting means at one'end thereof-t-he end remote from the toggle leverssueh support being secured to the door framework in such a way that movement of the piston'or plunger of the closer unit (and the corresponding movement of the toggle levers) causes a certain amount of oscillation of the closer unit about one end thereof, the horizontal distance from the door frame being a maximum at the point of connection between the plunger rod and the toggle levers. (This point of connection for convenience I term the crank pivot.) With such construction in. order to keep the amplitude of oscillation at a minimum (to conform to the space limitations usually encountered in the installation of sliding doors), the closer unit is usually so mounted with respect to the location of the pivot bearing for the toggle levers that opening movement of the doors carries-the crank pivot first inone direction laterally and then in the other, and in the vertical direction from a point a certain distance below the pivot bearing to a point substantially an. equal distance above the pivot bearing. The necessary consequence of this ai rangement, which as just'pointed out has usually been considered necessary because of space limitations, is to place upon the person desiring to open the doors the hurden of expending considerable effort in the initial opening act and a maximum effort during the half of the movement of the toggle lovers, the amount of this effort.

beingrepresented graphically .in Figure 4-. In tlns hgure, the point designated Ll'represents the location of the pivot bearing let and the point 17 represents the location. of the crank pivot 17 with the doors in closed position and the crank pivot and plunger in their lowermost.positions. The poiiits 17, 17 17 etc., represent the positions attained by the crank pivot at the completion ofsuccessive stages of the opening move ment of the doors. The horizontal distances from the vertical line 40 to the successive I-o I points 17, 1r-, etc., represent the relative amounts of force which, must be expended lite means by the operator of the doors to continue the" doors in their opening movement as the crank piv moves along the path indicated by the are 4-1. movement of the crank pivot and the toggleleversis represented. by the figure 19,'Which represents the i 'sistance oiiored by the closer unit 19 to the opening movj positions of-t he crank pivot are as indicated in Figure 4. An inspection of this figure shows that in order to give the door a 50% opening movement, it is necessary tor the operator'to expend a maximum of effort. Now, since an opening movement otthe doors less than 50% would be insufficient to permit passage of a person thru the openmg, it is apparent that no effective operation of doors equipped with the former type of closure operator can be obtained Without the expenditure of a maximum efliort on the part of the user or operator,'ancl further more, this maximum expenditure of effort must be made during the first portion otthe' opening movement rather than during the latter portion thereof.

Figure 5 represents by mea i'as of a similar diagram the increase in: efiiciency't-o beobtained by the use of the closure operating means oit't his invention. In thisfigure, as in Figure 4, the reference character 14: represents the location of the pivot bearing 1 and the point 17 represents the location of the crank pivot with the doors in closed position. Similarly the points 17, etc, represent the positions attained by the crank pivot at the completion of successive stages of the opening movement, the percentages ofthefopening movement corresponding to thedilterent positions illustrated in the figure. Now an inspection of Figure 5 reveals that a opening of the doors necessitates the expenditure of a minh smaller effort on the part of the operator, and consequently-With this new arrangement of the closure operatin apparatus, operation of the doors in theopening'direction becomes much easier and less fatiguing, inasmuch as a 50% or opening of the doors is all that is necessary as a practical matter for permitting the ordinary use of the. doors. The diagram further shows that the resistance offered to the opening T he resistance offered to the p movement, and hence the effort necessary:

toproduce opening movement, varies substantia y uniformly from a minimum at 1 .1a ion at the opening movement to a nim at substantially the end of a full opening n' iovem'enhv Another point to be noted in thiscon ncction is that the smaller the distance made between the vertiral line 40 and the point -17,the greater will be the ratio betw pltucle Of point 17; The efiect ot' this in terms of actual door operation is that the smaller the vertically projected distance becomes between the crank pivot 17 and pivot bearing 14, the greater becomes the ratio between the efi ort expended "to startthe' cloors on the opening movement and the effort expended at the latter part ofthe. open-mg movement. NOW masmuch as rt is desirable to make this ratio as large possible, thereby making the initial effort as small as possible, the crank pivot 17 is profsrabl'y disposed sothat it will normally restas near as possible to the door frame 15. Heretojfore, along with the practice of s g the closer unit at its lower end, a cra rk pivot has usually assumed'a position' comparatively remote from the door frame (asshown by the location of point 17 in Figure l), the normal angle of repose of former units being such as to produce this condition. By supporting the closer unit so as to obtain an angle of repose substantial'ly as shown in Figures 1 and'Q, it

becomes-possible to normally dispose the crank pivot much closer to the door frame (as shown by the location of point 17 in Figure 5). u

The-advantage of this disposition of the =n' the amp if-t udeof point 17 and the am-' crank pivot pin 17' lies in the reduction in the amount'ot lateral space necessary for the installation and operation of the closer unit which is thereby ciiectedj The ques-; tion of space is a very importantfaitor, particularly in elevator installations, to which this invention is applicable. Heretofore the use of an outwardly inclined angle of repose, orlat best, a vertical disposition, for the axislof the closer u'nithas necessarily limited the location of the crank pin 17 to a point removed from the door frame by a distance at least as great as the lateral eiitent of the supporting member plus the radius of thecylindrical closer unit. Hth the present arrangement, on the other hand, there is no such limitation on the proximity Which may exist between the crank pin 17 and the door frame.

This inwardly directed angle of repose may base-cured by the use of various locations for the supporting lug but inthe pre ferred form of the invention, as shown in Figures 1 and 2, I: choose to usethe location 22, which substantially midway between the ends of the closer units. By employing this location it is possible to reduce the amplitude of oscillation of the closer unit considerably in comparison to the amplitude of oscillation of the closer units of former constructions, even though the angle of oscil lation is just as great, or greater, than heretofore.

This result is shown graphically in Figure 6 where the point designated 22 represcnts the location of the supporting lug 22 of the present closer unit. In this figure also the point 22- designates the location hithertocommonly employed for the supporting lug on closer units of this type, this location ordinarily being the point opposite the lower end of the closer unit. Reference character 17 designates the location of the crank pivot of the present invention and reference character 17 the usual location of the crank pivot in similar units as formerly mounted. The line designated A represents the angle of repose of the closer unit of this invention and the line designated B represents the angle of repose of the closer unit with the mounting formerly employed. The dash line A represents the angle as sumed by the closer unit of the present invcntion when the doors are in full open positi on and the dash line B the angle assumed by the closer units with the mounting formerly employed when the doors are in full open position. Now inasmuch as the distance CD is less than one-half the distance CE, it is obvious that the closer unit of the present invention requires less than onehalf the lateral space required for similar closer units mounted in the manner formerly employed.

The great saving in valu'ble space thus attained by the use of my novel mounting means permits of the use of a much shorter stroke for the piston or plunger of the power unit without reducing the power in the closing movement beyond that customarily contained in closer units of the types heretofore used. The ratio of the two strokes is substantially the ratio of line MN of Figure 4 to line-OP of Figure 5, in that these lines fairly represent the amount of relative vertical. movement of the respective plunger rods of the prior art and of the present invention. Now since the stroke is reduced, it follows that the total deflection of spring 25 under compression (which equals the stroke of the. plunger) is correspondingly reduced.

This reduction in the amount of deflection allows the use of a coil of smaller diameter than heretofore, since the diameter of a coiled spring is a mathematical function of the springs deflection. Furthermore, the reduction in the amplitude of oscillation effected in the manner above described permits the use of a much longer springthat is, a spring with a greater number of turnsthan has been feasible heretofore. This increase in number of turns permits a vfurther reduction in the deflection of each turn, thereby reducing the strain and increasing the life of the spring. The result of these two improvements is a closer unit preferably of the proportions doors, or to other combinations of doors,

and also to other types of closures.

The above specification and the annexed drawings are to be considered only as illustrative of what I deem the preferred cm- The invention is bodiment at this time. not limited to this speoificform or to any particular combination or application of'the parts, but embraces all modified forms and constructions within the scope of the appended claims. I V 1 I claim: I

1. In a door operating structure for horizontally sliding doors, means for closing said door comprising a power unit, alever Connecting said power unit with the door, a pivot bearing about which said lever turns while said door is opening or closing, a sup porting lug for said power unit, manual means for opening said door against the re sistance of said power unit and means for relatively disposing said pivot bearing and said supporting lug so as to cause the re sistance ofieredby said power unitto increase continuously from a minimum value at the initiation of the opening movement to a maximum toward the end of the opening movement.

2. Apparatus as in claim 1, whereinthe' power unit is cylindrical in shape, and wherein the supporting lug supports the power unit at a point intermediate its ends, the lower end of the unit being free to oscillate about said intermediate supporting lug as the door is opened and closed. I v

3. In a door operating structure forhorizontally sliding doors, means for closing the door comprising a power unit, a lever connecting with the door at one end, a pivot bearing at the other end of said lever about which said lever turns while said door is opening, a crank pivot connecting said lever with said power'unit. manual means for opening said door againstthe resistance of said power unit, and means for relatively disposing said pivot bearing and crank pivot so as'to cause the resistance offered by said power unit to increase continuously from a minimum value at the initiation of the opening movement to a maximum at substantially the end of the opening movement.

4. Apparatus as in claim 3, wherein the increase in resistance is proportionate to the amplitude of a curve corresponding to the path of movement of said crank pivot while moving from door-closed to dooropened position. p

5. Apparatus as in claim 3 wherein means are provided for mounting said power unit in such position that said crank pivot is normally disposed a less distance in vertical projection from said pivot bearing than the distance from any point on theaxis of said power unit to the vertical projection of said pivot bearing.

6. In a door operatingstructure for horizontal sliding doors, means forclosing said door comprising a power unit, a plunger and plunger rod in said power unit, a lever connecting said plunger rod with the doors, means tending to maintain said plunger and plunger rod in their innermost positions in said power unit, means for retarding the movement of said plunger in the latter part of its movement toward its innermost position comprising a restricting passage permitting only a gradual escape of cushioning fluid, and means for permitting the free passage of said cushioning fluid around said plunger as it moves thru the first portion of its movement toward the innermost position comprising a plurality of cut-away portions in the wall of the power unit embracing said plunger.

7. Apparatus as in claim 6 wherein the wall of said power unit is cylindrical in formation and wherein the inner surface of said cylinder is provided with a serles of arcuate surfaces adaptedto act as guides for, said plunger said cutaway portions comprising depressions in the inner wall of said cylinder, said depressions being disposed between conse3utivearcuate surfaces.

8. In a door operating structure for horizontally sliding doors, means for closing the. door comprising a power unit, a plunger and plunger rod in said power unit, a lever connecting said plunger rod with the door,a pivot pin about which said lever turns while said door is opening or closing, a crank pin connecting said lever with said plunger rod, and means for mounting said power unit in such position that the normal angle of repose of said plunger rod maintains the said crank pin nearer to the vertical projection of said pivot pin than is any portion of said. plunger rod.

9. Apparatus as in claim 8 wherein the mounting means comprises a supporting memberintermediate the ends of said power unit and plunger rod, and about which said power unit is free to rock as the door is opened andclosed.

Signed at Hoboken, New Jersey, this 4th day of May, 1927.

HAROLD w. SHONNARD. 

